Which is better for charging a 12v battery, high volts or high amps?

Question

Would it be better and more efficient to charge a 12v battery with a generator that produces 350v and 15 amps at 2,000RPM or a generator that produces 50v and 50amps at 2,000RPM? In general which is better for charging, amps or volts?

Would it be better and more efficient to charge a 12v battery with a generator that produces 350v and 15 amps at 2,000RPM or a generator that produces 50v and 50amps at 2,000RPM? In general which is better for charging, amps or volts? I am doing a science project and basically I would have an inverter hooked up to the battery to change it to AC and run application off of it. But I want the application to run constantly so wouldn't that mean I would need to be generating enough energy to support these applications. If I got a charge controller that limited the amount of energy that is flowing into the battery from the generator wouldn't that battery go dead because it is putting out more energy than it is getting?

Answer 1

The generic answer to your question is that you will need a higher voltage ( than 12V ) to get more amps into the battery since you will have to overcome the battery's internal resistance which is the ultimately limiting feature of a charging situation.

However, your specific situation would lead one to prefer by far the 50V and 50 amp ( CAPACITY ) case since an overvoltage of 350V is likely to break down and short out some battery components.

Answer 2

Normally, the life of battery is shortened if it is charged with high current. However, if your generators are both DC and you think you can connect your battery directly, the rated voltage are too high. At most, you will be needing 13 to 14 volt dc to charge that battery. However, if the generators are AC, then you will be needing a charger whose DC output is okay for your 12-v battery. 15 Amp and 50 Amp are already high for this application.

Answer 3

First, the voltage is the real key property here. The battery will draw whatever current it wants at that voltage. For a lead acid car battery, anything over about 14.5 volts is overcharging, which heats the battery, possibly destructively. So, go find a charger that will limit to 14.5 volts and let the battery decide how much it wants in the way of current. If it is a car battery, it probably won't take more than a dozen amps at the beginning of the charge. Most of the chargers you get in the auto parts stores are 6 amps tops for home use.

So, watch the volts and let the amps take care of themselves.